Shielding



June 24, 1930. H. o. ETERSON 1,765,443

SHIELDING Filed Feb. 25, 1928 INVENTOR mom 0. PETERSON BY j Adm ATT RNEYPatented June 24, 1930 UNITED STATES PATENT OFFICE HAROLD OLAF PETERSON,OF RIVERHEAD, NEW YORK, ASSIGNOR TO RADIO CORPO- RA'JJION OF AMERICA, ACORPORATION OF DELAWARE SHIELDING Application filed February 25, 1928.Serial No. 257,088.

This invention relates to shielding, and more particularly to metallicshielding employed with alternating current apparatus to preventundesired magnetic and electric coupling.

Frequently alternating current apparatus must beshielded, either toprevent it from radiating energy, or, in the case of sensitiveapparatus, to protect it from the influence of interfering energy. Forthis purpose it is customary to surround the apparatus to be shielded ina metallic enclosure. If the shielded apparatus is to be accessible itis necessary to provide one of the shielding plates with an opening, orto make the enclosure with an. open side, and to cover the opening orside with a removable conductive plate.

The latter may be completely detachable, or

hinged, or pivoted, and I intend the term removable to comprehend allequivalent arrangements.

I find that the resulting break in the continuity of the shieldingdestroys its effective ness unless intimate conductive contact is madebetween the two plates, and to provide such contact is an object of myinvention. For this purpose I insert resilient conductive means between,the plates at the rim of the opening.

I prefer to make the resilient means in the form of-a conductive flangeof springy material,and I fix this flange to one of the plates. In ordernot to lessen-the accessibility of the enclosed apparatus I prefer toattach the flange to the removable cover, so' that it is entirely out ofthe way when the cover is removed.

It is essential that good electrical contact be made all around theperiphery of the cover, and even with a resilient flange this resultoften is not attained, owing to irregularities in the surfaces broughtinto contact. To make a more perfect electrical union, even betweensurfaces which are not perfectly plane, is a 45 further object of myinvention, which I fulfill by transversely slotting the resilientconductive flange all around its edge in order to form a plurality ofindependently yieldable flange portions.

The in enti n is described more in d a l in the following specification,which is accompanied by a drawing in which Figure 1 is a detail of apreferred form of flange;

Figure 2 is a View of the inside of a cover plate provided with aslotted flange; and

Figure 3 illustrates a metallic enclosure assembled with its removablecover.

Referring to Figure 1 there is a metallic enclosure 2, provided with anopening bounded by the edge 4. For closing the opening there is a coverplate 6, and between the plates 2 and 6 there Is provided a resilientconductlve flange 8, which is fixed on the cover plate 6 by means of aframe 10 attached to the cover plate by means of screws 12.

Referring to Figure 2 the cover plate 6 is seen to be, in this case,rectangular, and provided adjacent its periphery with a flange 8,

fixed to the plate 6 by means of the frame 10, which is screwed to theplate 6 by means ofscrews 12. It will be seen in this case that theflange 8 has been provided with a number of slots 14, so that it is madeup, in effect, of a plurality of independently yieldable flangeportions, thereby making possible more perfect electrical contact allaround the rim of the cover.

Figure 3 shows a complete metallic container 2 provided with a removablecover plate 6. The container may enclose any alternating currentapparatus which is to be shielded, whether to prevent radiation, or toinsulate from reception, through either magnetic or capacitive coupling.The cover 6,.

2. The combination With a' conductive shielding plate having an opening,and a re movable conductive shielding plate for coverings'aid opening,of a resilient conductive flange fixed to one of said plates in properposition to be between the plates and adjacent the rim of the openinwhen the plates are brought together, in order to insure good electricalcontact therebetween.

3. The combination with a conductive shielding plate having an opening,and a removable conductive shielding plate for covering said opening, ofa resilient conductive flange, transversely slotted to form a pluralityof independently yieldable flange portions, fixed to one of said platesin proper position to be between the plates and adjacent the rim of theopening when the plates are brought together, in order to insure goodelectrical contact therebetween.

4. In combination, alternating current aparatus to be shielded, ametallic enclosure or shielding said apparatus having an opening foraccess thereto, a removable metallic cover for said opening andresilient conductive means situated tween the cover and enclosureadjacent the periphery of the cover for insuring good electrical contactbetween the cover and enclosure. I

5. In combination, alternating current apparatus to be shielded, ametallic enclosure for shielding said apparatus having an opening foraccess thereto, a removable metallic cover for said opening, and aresilient conductive flange fixed to the cover adjacent its peripheryfor insuring good electrical contact between the cover and enclosure.

6. In combination, alternating current apparatus to be shielded, ametallic enclosure for shielding apparatus having an opening for accessthereto, a removable metallic cover for said opening, and a resilientconductive flange, transversely slotted to form a plurality ofindependently yieldable flange portions, fixed to the cover adjacent itsperiphery for insuring (good electrical contact between the cover anenclosure.

HAROLD OLAF PETERSON.

